This invention relates to a volumetric metering apparatus for dosing constant quantities of granular material and is of the type which has a cylindrical trough rotated about its axis and equipped with a plurality of metering receptacles which extend downwardly from a planar base of the cylindrical trough and which are continuously open at the top for communicating with the space within the trough. Further, above the trough base there is arranged a stripper or evener which has a radial dimension that is wider than the upward openings of the metering receptacles. Each metering receptacle has, at its lower end, a closing element which is opened when the metering receptacle assumes its filling position in a discharging station.
A metering apparatus of the above-outlined type is disclosed in German Offlenlegungsschrift (Non-examined Published Application) No. 2,424,063. The apparauts has a cylindrical trough having a planar horizontal base. A plurality of metering receptacles which continuously communicate with the trough are attached thereto such that they extend downwardly from the base and are arranged on a common dividing circle of the trough. With each metering receptacle there is associated a vibrating device to ensure that the granular mass is maintained constant in the individual receptacles. At the lower end each receptacle is closed off by a plate member which is in an open position when the respective metering receptacle is in a discharge position. Above the metering receptacle which dwells in the discharge position, a stationary evener is arranged which limits the level of the granular material contained in the metering receptacle. In case the granular material has relatively coarse granules, the evener has an undesired shearing effect on the granular material passing thereunder. This phenomenon leads to irregularities in the surface of the granular material with which the metering receptacles are filled. As a result, the metered material quantities are disadvantageously lacking uniformity. A similar metering apparatus is disclosed in German Auslegeschrift (Examined Published Patent Application) No. 1,424,089.
In the metering apparatus disclosed in U.S. Pat. No. 4,192,359 no dosing receptacles are present; rather, packaging containers for beans are being filled. The beans are introduced into a rotary trough which is provided with openings below which the containers are disposed. Prior to removing the containers, they pass below cylindrical brushes rotated about a horizontal axis.